Transfer resources

Transfering resources between different fhir servers was the original reason for the creation of this library. In the FHIR format this poses significant challenges as referential integrity is strictly enforced and batched transaction do not autmatically resolve the order of object creation and server generate id assignment.

To solve this problem the FhirServer class has a transfer() method that can be used to transfer resources from one server to another. This method accepts either a list of fhir.resources objects that are required to have a server assigned id and resource_type attribute or a FhirQuery object whose results should be transfered. Additionally, the transfer() method accepts a target_server argument that is a FhirServer object that represents the server to which the resources should be transfered.

In the default configuration the provided resources (either the list or the results of the executed query) are then analyzed for missing references. If any are found, the FhirServer will attempt to resolve them by querying the source server for the missing resources. If the missing resources are found, a DAG is created that represents the order in which the resources should be created on the target server. This DAG is then used to create the resources on the target server in the correct order keeping the referential integrity intact.

Record Linkage

The transfer() method also supports record linkage. In this case this means that while transfering the newly created reference for the transfered resource will be stored in a dictionary with the hashed original reference as key. This allows back linkage from the transfered data to the data in the potentially sensitive source server with out comprosing any IDs.

Example Usage

This example will show the transfer of the first 100 conditions from one server to another. While also transfering all referenced Patient resources

from fhir_kindling import FhirServer

src_server = FhirServer(api_address="http://fhir.example.com/R4")
target_server = FhirServer(api_address="http://fhir-2.example.com/R4")

# Get a list of 100 conditions
patients = src_server.query("Conditions").limit(100).resources

# Transfer the conditions to the target server
# this will also transfer all referenced resources (Patient, Observation, etc.)
transfer_response = src_server.transfer(resources=patients, target_server=target_server)
print(transfer_response)

Transfer API

transfer(self, target_server, query=None, resources=None, get_missing=True, record_linkage=True, display=False)

Transfer resources from this server to another server while using server assigned ids and keeping referential integrity.

Parameters:

Name	Type	Description	Default
target_server	FhirServer	FhirServer to transfer to	required
query	FhirQuerySync	FhirQuerySync to use to find resources to transfer	None
resources	List[Union[fhir.resources.resource.Resource, fhir.resources.core.fhirabstractmodel.FHIRAbstractModel]]	list of resources to transfer	None
get_missing	bool	whether to get missing references from the source server	True
record_linkage	bool	whether to record the linkage between the source and target server	True
display	bool	whether to display the progress bar	False

Returns:

Type	Description
TransferResponse	Transfer response for the transfer of the query result to the target server